# Test 3b: Z₁ × Event Time — Gradual vs Discrete Fade

*If the demographic effect fades gradually → composition/learning. If discrete break at opening → structural disruption.*

## Model 1: Continuous Fade (Z₁ × event_time)

| Variable | Coefficient | SE | p |
|:---|---:|---:|---:|
| Z_1 | 46.503 | (65.169) | 0.476 |
| Z_2 | -6.970 | (9.630) | 0.470 |
| Z_3 | 0.268 | (0.394) | 0.498 |
| event_time | -0.008 | (0.160) | 0.961 |
| Z_1_x_event_time | 0.383** | (0.163) | 0.020 |

*R² = 0.0787, N = 339*

## Model 2: Discrete Break (Z₁ × post_opening)

| Variable | Coefficient | SE | p |
|:---|---:|---:|---:|
| Z_1 | 67.453 | (70.009) | 0.336 |
| Z_2 | -12.632 | (10.309) | 0.221 |
| Z_3 | 0.576 | (0.418) | 0.169 |
| post_opening | -0.975 | (1.269) | 0.443 |
| Z_1_x_post | -0.304 | (1.125) | 0.787 |

*R² = -0.0241, N = 339*

## Interpretation

- Continuous fade Z₁×event_time: p = 0.020
- Discrete break Z₁×post: p = 0.787
*Gradual fade significant, discrete break not → composition/learning effect.*

*Event window: [-10, +15]. Transition economy openers only.*
*Controls: fiscal_bal_gdp, nfa_gdp_lag, trade_openness, log_rel_opw.*